Lecture Notes in Computer Science 3472

346 Levi Lúcio and Marko Samer
It is now possible to calculate the boundary states. These correspond to
states in the execution space of the specification where at least one of the
state variables assumes a boundary value. Symbolic execution is again necessary
at this stage given that in order to know the ranges of all the other
state variables that define a boundary state it is necessary to know the path
condition for that state.
Final state
of body 1.1
Final state of
identification
Boundary Boundary
state 1
state 2
Final state of
identification
...
Initial State
Final state Final state
of body 1.2
of body 1.m
Final state of
identification
Fig. 12.6. Trace construction for boundary testing
...
Boundary
state m
preamble invocations
body invocations
identification invocation
postamble invocations
• generate the test cases (traces through the state space): this activity may be
resumed to the following:
– Calculate the preamble trace to the boundary state: this consists of calculating
the sequence of operations that leads the system to a boundary
state. Given that the path condition for the boundary state is already
known, this can be considered trivial;
– Calculate the “critical invocation” step: the authors of the approach define
critical invocation as the execution of the operations which are possible
from the boundary state. The execution of these operations in is
clearly sensitive since is implies the manipulation of a boundary value.
For that reason the input parameters for the operations under analysis
are decomposed into subdomains as was done in order to find the boundary
values. We can say that the operations accessible from the boundary
state are then symbolically executed over their entry parameters, yielding
a subdivision of the preamble trace (see Fig. 12.6);